Vacuum controlled caution signal for automobiles



Nov. 25, 1941.

Filed Feb. 7, 1941 7 .Il Ii -31 6) I. T 32 {i r/ 13 13 1? l3 8% 1 t h 5 37 I?) l? f 55? la I I0 {I I: i

9 I ,1: +1. 9'", n W 23 1 /5 /e/16 u 6- 25 29 W Flt?! 6 36 25 a 39 INVENTOR 2 8 \8 1 \J.H.GLASHAN 27 FIG. 3

M ATTORNEZS Patented Nov. 25, 1941 VACUUM CONTROLLED CAUTION SIGNAL FOR AUTOMOBILES John Homer Glashan, Mount Royal, Quebec, Canada Application February 7, 1941, Serial No. 377,885

3 Claims.

This invention relates to an improved vacuum operated switch mechanism for actuating a warning signal on an automobile.

When an automobile is operating in traflic or is approaching an intersection at ordinary running speeds, it is frequently necessary for the operator to slow down the automobile by removing his foot from the accelerator pedal and permitting the throttle to close. This enables the operator to take advantage of the braking effect obtained when the engine is running on compression. It also causes an increase of the suction created in the intake manifold of the engine.

The present invention is designed to take advantage of the operating conditions existing when the engine is running on compression. It consists in the provision of a vacuum operated switch which is connected to the engine intake manifold so that the switch is repeatedly closed and opened by the increased suction created in the manifold when the accelerator pedal is suddenly released, the repeated opening and closing of said switch being utilized to effect repeated operation of a warning signal during the period that the suction in the intake manifold is above a predetermined value. In the preferred embodiment of the invention, the warning signal comprises a signal lamp which is connected in circuit with the switch and a suitable source of current so that the lamp is energized and deenergized as the switch is repeatedly closed and opened by the suction in the manifold. It will be understood, however, that the signal lamp may be replaced by any suitable form of electro-responsive mechanical signal capable of being operated in response to opening and closing of the Vacuum operated switch.

Proceeding now to a more detailed description of this invention reference will be had to the accompanying drawing, in Which- Fig. 1 is a diagrammatic view showing the manner in which the vacuum operated switch is connected in circuit with the warning signal and the source of current.

Fig. 2 is a central longitudinal sectional view of the switch with the component parts thereof arranged in open circuit position.

Fig. 3 is a View similar to Fig. 2 but showing the component parts of the switch in a circuit closing position, and

Figs. 4 and 5 are views similar to Figs. 2 and 3 but showing the component parts of the switch in different positions.

As shown in the drawing my improved switch comprises a piston 5 working in a cylinder 6 provided with removable end heads I and 8. The head I is provided with a central opening in which is fitted a bushing 9 made of insulating material. A metal tube l0 extends downwardly through said bushing and is held against movement relative thereto. The lower end of the tube I0 is enlarged or flanged outwardly to form a stationary contact disc II. The upper end of the metal tube is provided with a lateral extension l2 which is connected, by tubing l3, or in any other suitable manner, to the intake manifold (not shown) of an automatic engine. The stationary contact disc I l is engaged, at times, by a movable contact disc l4 provided with a stem I5 which extends loosely through a central opening I 6 of the piston 5. The lower end of stem [5 is connected, by a spring H, to the bight portion of a U-shaped member [8 the side arms of which are fastened to a metal washer l9 which, in turn, is clamped against the piston washer 20 by means of the clamping nut 2| which is threaded onto a tubular extension 22 of the piston 5. The stem l5 of contact M is provided with an enlargement 23 which serves as a stop which bears against the piston 5 when the parts of the switch are arranged as shown in Figs. 2, 3 and 5.

A spring 24, which is stronger than the spring I1, is connected between the bight portion of the U-shaped member [8 and a spring tension adjusting member 25. The member 25 is provided with a threaded shank 26 which extends slidably through a central opening of the cylinder head 8 and is fitted with an adjusting nut 21. Obviously, by turning the nut 21 the spring adjusting member 25 may be moved toward or away from the cylinder head 8 to vary the initial tension of the spring 24. It may be noted here that the movable contact I4 is grounded through spring [1, U-shaped member [8, spring 24, member 25 and nut 21 to the cylinder 6. Contact I 4 is also grounded to the cylinder 6 through the valve enlargement 23 of stem [5 and the metal piston 5. On the other hand, the stationary contact I I is completely insulated from the cylinder head I by means of the insulating bushing 9.

As shown in Fig. 1, the metal tube ID of the stationary contact II is connected, by conductor 30, to one terminal of a battery 3| or other suitable source of current, the remaining terminal of which is connected, through signal lamp 32, to the cylinder 6. It is thus obvious that the signal lamp 32 is energized whenever the movable switch contact 14 is engaged with the stationary switch contact II and is deenergized when these contacts are separated.

When the automobile to which my invention is applied is running at ordinary operating speeds, the suction created in the engine manifold is insufficient to close the switch. When, however, the operator removes his foot from the accelerator the increased suction created in the manifold acts, through the flexible tubing [3 and the metal contact tube ID, to move the piston 5 and the movable contact [4 from the circuit opening position shown in Fig. 2 to the circuit closing position shown in Fig. 3. The movahle contact 14 is thus brought into engagement withthe stationary contact I l and the spring 24 is stressed soon as the piston has made a slight downward movement the upper end of the central opening of the piston is uncovered and permits a greater volume of air to rush into the upper portion of the cylinder to facilitate further downward movement of the piston by the spring 24.

Having thus described what I now consider to be the preferred embodiment of this invention it will be understood that various modifications may be resorted to within the scope and spirit of the invention as defined by the appended to a considerable degree. No relative movement takes place between the piston 5 and the contact I4 as these parts travel from the position shown in Fig. 2 to the position shown in Fig. 3. .Inthis connection it will be understood that the suction r vacuum r ate .1. he upper end of t e c l m der acts mainly on the upper surface of the piston 5 owing to the fact that the area of said surface is considerably greater than the area of the movable contact 14. -When the movable contact l4 reaches the position'shown in Fig. 3, it closes off the lower end of the bore or passage of tube LI] and thus disrupts the connection between the switch cylinder and the intake maniiold. When this occurs the vacuum in the portion of the piston above the cylinder is relieved by 'l'eason off the fact that a certain amount of air entering the lower portion of the cylinder through the air vents 29 passes through the piston opening 16 and groove 23a of stop 23 into the portion of the cylinder above the piston and this permits the spring 24 to effect a return movement of the piston 5 from the position shown in .Fig. 3 to approximately the position shown in Fig. 4. During this travel from the position shown in'Fig. 3 to the position shown in Fig. 4 the piston 5 moves downwardly independently of the contact 14 which is still held to the contact H by the suction acting through the bore or passageway of the metal tube l0. When, however, the piston 5 reaches the position shown in Fig. 4 the spring lfl is stretched to such an extent that it exerts a downward pull on the contact M which is suffie cient to return said contact toits initial position with respect to piston 5 as shown to advantage in Fig. 5. As soon as the contact 14 is snapped back from the positionshown in Fig. 4 to the position shown in,Fig.,5 the suction through tube l0 causes the piston 5 and the contact [4 to immediately return to the circuit closing position shown in Fi 3. This alternate opening and closing of the switch continues until the automobile has slowed down to the point where the suction in the manifold drops below the value required to operate the switch. From this it will be'seen that the switch acts as a flasher switch since it .causes the the warning signal to be energized and deenergized a number of times immediately following the releasement of the accelerao dal- The ea a o a u w dl pas e pis 5 when the parts are in the position shown in Fig. 2 breaks t e vac um in the up er po n f the cyiinder sufiiciently to enable the spring 24 to start the downward movement of the piston. As

claims.

I iaving thus described my invention, what I claim is:

1. A vacuum operated switch of the character described comprising a cylinder, a piston operating therein, a spring normally arranged to urge said piston in a switch opening direction, a tube through which suction is applied to move the piston in a switch closing direction against the resistance of said spring, a travelling contact carried by said piston and a stationary contact against which the travelling contact-is moved when suction is applied to move the piston against the action of said spring, means whereby the application of suction through said tube is discontinued when the contacts of the switch are brought into engagement with each other and means ior supplying air to said cylinderto break the vacuum previously created therein by the suction applying means so that said spring thereupon becomes eiiective to return the piston and piston carried contact to a circuit-opening posi tion.

2. A switch as set forth in claim 1, in which, foi lowing the breaking of the vacuum in the cyl. nde an th 're ur of he Pi ton o a rc topeni-ng position the vacuum is immediately reestablished in the cylinder to effect a further moyement of the piston to a circuit-closing position.

7 3. A vacuum operated switch of the character descriiced comprising a cylinder, a tube extending into said cylinder through one end thereof, a stationary contact positioned at the inner end. of the tube and insulated from said cylinder, means for connecting the outer end of the tube to the intake manifold of an engine, a piston working in said cylinder, a spring connected between the piston and the endof the cylinder remote from said tube, .a movable contact slidably arranged in an opening in said piston and a spring con motion between said movable contact and said piston, the arrangement being such that the suction in the engine manifold acts through said tube to move the piston in the direction of the tube until the movable contact is broughti-nto engagement With the stationary contact, said movable contact then serving to block the inner end of the bore or passage. of said tube and to thereby disrupt communication between the cyl-i nder and the engine manifold so that the first mentioned spring becomes effective to move the piston in a switch opening direction, the movable contact remaining stationary until the spring connection between this contact and the piston is sufficient to overcome the suction acting to hold the mOVr able contact engaged with the stationary contact.

JOHN HOMER SHAN. 

